The present invention generally relates to electrochemical cells and, more particularly, to a method of assembling an electrochemical cell having a non-cylindrical container.
Conventional alkaline cells commonly employ a cylindrical shaped steel can provided with a positive cover at one end and a negative cover at the opposite end. The cylindrical steel can houses a positive electrode, referred to as the cathode, which is preferably formed of a mixture of manganese dioxide, graphite, potassium hydroxide solution, deionized water, and other additives, and the cathode is commonly formed about the interior side surface of the cylindrical steel can. A cup-shaped separator is commonly disposed about the interior surface of the cathode. A negative electrode, referred to as the anode, which is typically formed of zinc powder, a gelling agent, and other additives, is dispensed within the separator along with electrolyte solution.
Conventional cylindrical cells are widely available in sizes AAAA, AAA, AA, C, and D for use as the power source for various electrically operated devices. Despite the popularity of the conventional cylindrical cells, it has been discovered that there is a potential need to provide for non-cylindrical cell configurations. One such potential need exists for use in a multiple-cell battery, such as the 9-volt battery, which commonly houses six 1.5 volt cells electrically connected in series. In the past, multiple cylindrical cells have been assembled together in a rectangular container, thereby resulting in unused space between adjacent cells as well as between each cell and the inside walls of the battery container. In addition, it has also been discovered that many battery operated electrical devices are capable of using noncylindrical cells which may allow for increased service performance. An example of a noncylindrical cell is disclosed in co-pending U.S. application Ser. No. 09/110,119, pending entitled "Electrochemical Cell and Battery" filed on Jul. 2, 1998, to Lewis Urry, which is hereby incorporated by reference.
A primary goal in designing alkaline batteries is to increase the service performance of the cell. Another goal is to achieve high quality cell assembly techniques. The service performance is the length of time for the cell to discharge under a given load to a specific voltage at which the cell is no longer useful for its intended purpose. Commercially available alkaline cells and batteries have an external size that is commonly defined by industry standards, thereby limiting the ability to increase the amount of active materials within a given cell and to confine the volume that is available. Accordingly, the need to find new ways to increase service performance and provide suitable assembly techniques remains a primary goal of the cell designer.